The first thing you have to do is try to see whether you can follow the beat of songs that you listen to while using your hands on a music box. A music box is basically a hollow box which when you tap your hands on it will give out a drum kind of sound.
Practice as much as you can following the beat of the music. Sometimes use your hands and others use drum sticks and see how you go.
If you think that you can follow the rythmn quite well then now is the time to go and buy youself a drum set. There are many to choose from. You can opt for the whole drum set, or just buy two drums to get started with.
Put on your favourite music and just try to accompany it. Listen to the drummer on the song and see if you can make the same sounds as he does.
I think that playing the drums is just a matter of lots and lots of practice and trying to get your hands to go with the music.